1. Field
Exemplary embodiments of the present invention relate to semiconductor design technology, and more particularly, to an address detection circuit, a memory, and a memory system.
2. Description of the Related Art
As the degree of integration of memories increase, a space between word lines included in a memory, such as dynamic random-access memory “DRAM”, is decreased. Due to the decreased space between the word lines, a coupling effect between adjacent word lines increases. Thus, when a specific word line of the memory is activated an excessive large number of times or activated frequently between refresh operations, data of memory cells connected to a word line adjacent to the specific word line may be degraded. Such a phenomenon is referred to as word line disturbance or row hammer. Due to the word line disturbance, the data of the memory cells may be degraded even within a retention time of the memory cells to be refreshed
FIG. 1 is a diagram illustrating a part of a cell array included in a memory for describing the word line disturbance.
In FIG. 1, BL and BL+1 represent bit lines, and WLK−1, WLK, and WLK+1 represent three word lines disposed sequentially within the cell array. Among the word lines WLK−1, WLK, and WLK+1, WLK with “HIGH_ACT” corresponds to a frequently activated word line, a high active word line or a word line having the large number of activations, that is activated at a high frequency, and WLK−1 and WLK+1 correspond to adjacent word lines, which are disposed adjacent to the frequently activated word line WLK. Furthermore, CELL_K−1, CELL_K, and CELL_K+1 represent memory cells connected to the word lines WLK−1, WLK, and WLK+1, respectively. The memory cells CELL_K−1, CELL_K, and CELL_K+1 include cell transistors TR_K−1, TR_K, and TR_K+1 and cell capacitors CAP_K−1, CAP_K, and CAP_K+1, respectively.
When the frequently activated word line WLK is activated or precharged i.e., deactivated, the voltages of the adjacent word lines WLK−1 and WLK+1 increase or decrease due to a coupling effect occurring between the frequently activated word line WLK and the adjacent word lines WLK−1 and WLK+1. Accordingly, the amount of charges charged in the cell capacitors CAP_K−1 and CAP_K+1 is affected, so that the data stored in the memory cells CELL_K−1 and CELL_K+1 may be degraded.
Furthermore, electromagnetic waves generated while the word line toggles between the active state and the precharge state introduce or discharge electrons into or from the cell capacitors included in the memory cells connected to adjacent word lines, thereby degrading the data of the memory cells